1. Technical Field
The present invention relates to an electroluminescence device, a method of manufacturing the electroluminescence device and an electronic apparatus.
2. Related Art
As a display device used for an electronic apparatus such as a mobile phone, a personal computer or a personal digital assistant (PDA) or an exposure head in an image forming apparatus such as a digital copier or a printer, a light emitting device such as an organic electroluminescence device (hereinafter, abbreviated to organic EL device) is attracting much attention.
Such a light emitting device, in order to realize color display, a configuration for emitting light of each color from each pixel by changing the material of a light emitting layer for each pixel has been known.
As disclosed in Japanese Patent No. 2,797,883, a technology of forming an optical resonator between a lower reflection layer formed below a light emitting layer and an upper reflection layer formed above the light emitting layer, changing a film thickness of a pixel electrode formed of indium tin oxide (ITO) to change an optical length of the optical resonator for each pixel, and extracting light of each color from light emitted from a light emitting element is suggested. When a bottom emission type organic EL device for emitting light from a light emitting layer to a substrate is configured using the disclosed technology, the lower reflection layer is formed of a semitransparent reflective layer. When a top emission type organic EL device for emitting light from a light emitting layer to the opposite side of a substrate is configured, the lower reflection layer is formed of a metal film having high reflectivity, such as aluminum or silver.
However, in order to form anodes having different film thicknesses by an ITO film, the ITO film is formed, a resist mask is formed on the ITO film using photolithography, and etching is performed. To this end, in order to cause the thicknesses of the anodes to be different from one another in a red pixel, a green pixel and blue pixel, the above-described step must be repeated at least three times.
As a result, the lower reflection layer is etched by etchant or etching gas used for etching the ITO film and thus the reflection property of the lower reflection layer deteriorates or lack of the lower reflection layer is caused. The etching of the lower reflection layer is not limited to the termination of the etching in which the lower reflection layer is exposed from the ITO film, and may be caused just after the beginning of the etching when a minute hole is formed in the ITO film.
In order to change the thickness of the anode for each pixel, for example, a method of changing an etching time for each of the three steps is considered. When the etching time varies depending on the step, it is difficult to manage the process. In addition, a side edge may be generated by increasing the etching time.
Since the ITO film is formed by plural steps, the steps become complicated and thus productivity deteriorates.